1. Field of the Invention
This invention relates to an information recording or reproducing apparatus and more particularly to an information recording or reproducing apparatus which is capable of detecting the travelling status of a recording medium in use.
2. Description of the Prior Art
In this specification, a magnetic tape will be used as an example of the recording medium while a video tape recorder (hereinafter will be called VTR's) adapted for recording or reproducing video signals will be used as an example of apparatuses to which the present invention is applicable. VTR's of the type that use a non-endless magnetic tape are arranged such that, when the magnetic tape is completely wound on one of reels, the reels cease to rotate. In that instance, a reel driving arrangement must be disengaged from the base of the reel, otherwise a belt idler and the like will begin to slip. The slippage then tends to cause rubber components or the like to deform by abrasion, and so forth.
To prevent this, it is necessary to provide the VTR with some end stop means for stopping the apparatus when the tape is wound up on one of the reels. Heretofore, a method for stopping the rotation of a reel hub has been employed for this purpose. This conventional method, however, requires some length of time to elapse before the apparatus stops after the tape has come to an end. During this length of time, the above stated deformation and other difficulties still occur. Besides, where both ends of the tape are provided with leader tapes, the leader tape contacts a rotating magnetic head and jams the surface of the head.
To solve this problem, in another conventional method, a transparent leader tape is used as an optionally detectable element. In that method, however, the optical detecting means includes a light emitting (or receiving) member that is inserted in the tape cassette and a light receiving (or emitting) member that is disposed opposite to the light emitting (or receiving) member across the tape. The two leader tape detecting members must be arranged in respective positions in which the tape is interposed in between them not only in a tape loading condition but also in a condition in which the tape is placed within the cassette. In the case of a magnetic tape device using a small cassette, this requirement has resulted in a complex structural arrangement for both the cassette and the device. This structural complexity has hindered efforts to attain reduction in size as well as construction simplification for the apparatus.